1. Field of the Invention
The present invention relates to an ink jet recording device having a manifold fluidly connecting an ink cartridge with an ink jet head, and more specifically to the ink jet recording device capable of reliably discharging air bubbles from the manifold by purging operations.
2. Description of the Related Art
A conventional ink jet recording device includes an ink jet head having actuators. The actuators are formed from an electromechanical converting element or electrothermal converting element, and define a plurality of ink chambers aligned in a row. An ink cartridge storing ink is detachably attached to the ink jet head by a manifold. The manifold is formed with an ink supply path that normally broadens from the ink cartridge side to the ink jet head side so as to encompass the entire row of ink chambers. Ink in the ink cartridge is supplied through the ink supply path of the manifold into the ink chambers. When the actuators are energized, ink is ejected from the ink chambers through nozzles to form an image on a recording medium.
Normally, purging operations are performed when the ink cartridge is exchanged for a new one. Specifically, during the purging operations, suction force is applied to the nozzles of the ink jet head so as to introduce fresh ink from the new ink cartridge into the ink chambers. At the same time, air that was introduced into the manifold during exchange of the ink cartridge is discharged out of the ink jet head along with some ink.
However, when the air forms a single spherical air bubble that floats freely in the broad portion of ink supply path, ink flows around the air bubble during the purging operations. As a result, a sufficient pressure for discharging the air bubble may not be generated within the manifold. As a result, the air bubble remains in the ink supply path without being ejected during the purging operations. Also, because the air bubble itself has a relatively large volume, by coupling with micro-air bubbles dissolved in the ink, the air bubble can quickly grow to a sufficient extend to clog up the inlets to the ink chambers. As a result, shortly after the ink cartridge is exchanged, printing can become defective due to improper ejection of ink from the ink chamber.
Also, air introduced into the ink supply path during exchange of the ink cartridge may remain in the ink supply path without being discharged, because of changes in ink viscosity by temperature, variation in suction force generated by the purging operation, or other indefinite reasons.